I'd be glad to provide the information you need, ruchir-vaishnav.
The contribution will decrease the amount on box 2 of the 941, and will not be reported on the 940 forms. You can check out this article on how the it is reported on the other federal forms: Supported pay types and deductions explained. Go to the 401(K) / 401(K) catchup section.
If you need more clarifications, please don't hesitate to get back to me. Have a good day!
